An "Ampere" is a measure of electrical current. It is equal to one Coulomb of charge passing a point in one second. An "Ampere hour" is one Ampere current running for one hour. Since one Ampere is equal to one Coulomb of charge per **second**, and there are 60x60= 3600 seconds in an hour, "one Ampere hour" is equivalent to 3600 Coulombs of charge. 40 Ampere hours is 40x 3600= 144,000 Coulombs of charge.

But the difficulty with your question is that "Coulombs" are not a measure of energy. There is NOT a specific amount of energy in "40 Ampere hours".